Re: [Qemu-devel] [PATCH 41/52] isa: express dependencies with kconfig

[Philippe Mathieu-Daudé]

On 1/31/19 11:14 PM, Paolo Bonzini wrote:
> On 31/01/19 22:22, Philippe Mathieu-Daudé wrote:
>> I kinda disagree with the SuperIO generated configs here, but partly my
>> fault because the previous Makefile.objs missed the CONFIG_ISA_SUPERIO
>> (I missed to review eae2e2e96bf from Thomas where is introduced
>> CONFIG_SMC37C669).
>> So introducing ISA_SUPERIO simplifies this files and SouthBridge
>> devices. I'm not sure how to provide this patch:
> 
> The problem is different SuperIO chips can have or lack
> floppy/serial/parallel, and so they end up having different dependencies.
> 
> Config symbols are a tool to generate working QEMUs (where working =
> build and pass device-introspect-test more or less), they needn't
> reflect precisely the topology of the machine.

The model implementation is:
- abstract SuperIO parent which can instantiate all configs,
- child implementation.

Childs require their parent, and even if the parent will instantiate
them without all properties, the parent needs to link with them.

In short, if a SuperIO child requires ISA_SUPERIO, it also requires to
link to serial/parallel/floppy/ide.

That's why I prefer the explicit dependencies.

Oh, actually if we correctly use the TYPE_XXX names, it might link.
The only problem would be trying to instantiate a device via QMP then?